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c++boostposix

Average of multiple ptime

I am trying to find the average UTC time of when a function was called. So I do:

    boost::posix_time::ptime  current_time_before(boost::posix_time::microsec_clock::universal_time());
    DoStuff();
    boost::posix_time::ptime current_time_after(boost::posix_time::microsec_clock::universal_time());

How do I go about calculating the averages between these two times? I tried: 

double time_avg = (current_time_before+current_time_after)*0.5;

But I get an error on a linux system that seems to have a problem with "+" but not "-" .

Thank you for your help.

Solution

  • Just... write it naturally?

    ptime midpoint(ptime const& a, ptime const& b) {
    return a + (b-a)/2; // TODO check for special case `b==a`
}

    Live demo:

    Live On Coliru

    #include <boost/date_time/posix_time/posix_time.hpp>

using boost::posix_time::ptime;

ptime midpoint(ptime const& a, ptime const& b) {
    return a + (b-a)/2;
}

int main() {

    ptime a = boost::posix_time::second_clock::local_time();
    ptime b = a + boost::posix_time::hours(3);

    std::cout << "Mid of " << a << " and " << b << " is " << midpoint(a,b) << "\n";
    std::swap(a,b);
    std::cout << "Mid of " << a << " and " << b << " is " << midpoint(a,b) << "\n";
}

    Prints

    Mid of 2016-Sep-15 11:17:10 and 2016-Sep-15 14:17:10 is 2016-Sep-15 12:47:10
Mid of 2016-Sep-15 14:17:10 and 2016-Sep-15 11:17:10 is 2016-Sep-15 12:47:10